I've run Intel(R) processor identification and got this result , i don't know why my CPU only run at 0.79Ghz while it can up to 2.30Ghz . Is it normal ? And Turbo boost seem doesn't work , the status bar never move a little bit . Can anyone help me ? I'm so confused.

Since only the processor was given then statements will only based on the cpu. It should be operating from 2.3 Ghz to 2.9 Ghz. If you provide additonal info about your system it should help a lot for anybody willing to help you.

From the picture, the system bus is 100 Mhz. Should it not be 133 Mhz? If you read the FAQ of TurboBoost monitor each bar is an increment/decrement of 133 Mhz. I'm not sure about this since I don't have a Dell system like yours.

Try running another program to confirm that the cpu is running at 0.79 Ghz. You can download and run the open source program "Open Hardware Monitor".

It looks like the laptop is running in single core only. There should be two cores shown in Open Hardware Monitor. I'm not sure if you have the option in bios to change the number of cores. If not you really have to consult Dell about it.

This is my first generation i5 cpu. It is a quad core cpu thus there are four cores shown in Open Hardware Monitor and also in CPU-Z. Looking at your CPU-Z result your pc is running in single core (see bottom "cores" entry in CPU-Z). Also your cpu is running at a high temperature.

As stated earlier you go to bios and set the number of cores. Set it to "all". This is for Intel motherboards. Since you have Dell you should ask Dell Tech support about it if you cannot see that option in the bios.